As you're probably well aware, no matter how much they claim to be non-drowsy, antihistamines (think: Allegra, Benadryl, Claritin, and Zyrtec) can sometimes make you feel tired and just plain out of it. That's because the pills also have also suppressive effect on the central nervous system, which can interfere with your body's normal processing of this-should-turn-you-on cues.

Plus, research, including one study in the British Journal of Urology, shows that histamines (not to be confused with antihistamines) actually spur erections by acting on the corpus cavernosum, a spongy strip of tissue that runs up the shaft and soaks up blood to help make you hard.

"What I observe more commonly in patients is that antihistamines are often combined with Sudafed, a known vasoconstrictor that leads to decreased blood flow to the penis and suppresses erections," he says.

So if you notice things going soft this allergy season, Paduch recommends avoiding antihistamines combined with Sudafed (aka pseudoephedrine). Hopefully the script can help you score everything you want from spring—both in the bedroom and the great outdoors.